summarizes key observations and concepts concerning the involvement of the motor cortex in [the] motor cognitive processes operating on the direction of movement in space / large populations of neurons in motor cortex are engaged with reaching movements / single cells are directionally broadly tuned, but the neuronal population carries an unambiguous directional signal / the outcome of this population code can be visualized as a vector that points in the direction of the upcoming movement during the reaction time, during an instructed delay period, and during a memorized delay period / moreover, when a mental transformation is required for the generation of a reaching movement in a direction different from a reference direction, the population vector provides a direct insight into the nature of the cognitive process by which the required transformation is achieved (PsycINFO Database Record (c) 2019 APA, all rights reserved)